At present, numerous USB devices in the market have a switching process from a disk working mode to a multi-port working mode. If a host is not installed with a user interface (user interface, UI) program and a driver, then a USB device will report information of a single disk CDROM-class device after connecting to a computer, wherein the CDROM includes a UI program and a driver required for the USB device in the multi-port mode. After installation is completed, the UI or the driver will automatically detect the USB and send a specific instruction to make the USB device switch from the disk working mode to the multi-port working mode.
The current common solution has drawbacks in principle as follows:                (1) no matter whether or not the UI or the driver has been successfully installed in the host, a USB device is firstly enumerated as a CDROM-class device each time when the USB device is inserted into the host, wherein the UI or the driver of the CDROM detects if programs that are required for the device to work normally have been installed in the host. If no such programs have been installed, then the disk state is maintained and a user is reminded of installation. If such programs have been installed, then a switch instruction is sent, causing the device to switch to the multi-port working mode. The process of the working mode switching normally requires the USB device to reconfigure firmware programs by cutting off power supply. However, such a switching mode is time consuming, and the time cost is detrimental to improving user experience; and moreover, such switching mode brings about compatibility problems for the firmware programs and UI programs of the USB device.        